Allow numeric cells to be "empty"
Allow numeric cells to be "empty"

This simple change allows numeric cells to be empty, rather than forcing a value. For example, a "Sale Price" field. if it's empty there's no sale price, but with the current script it'll force to `0` making the item free.

Once merged, simple add `allowEmpty: true` to the `columns` parameter.
paulhodel/jexcel,paulhodel/jexcel